"Captain Pizza disagrees with the very rules that brought
him to the mayor's seat," Grillo wrote on his blog.

Voted in as mayor in May 2012, Pizzarotti, 41, was the
first candidate to bring the M5S to power in a large city.
Movement leader Grillo often invited him to share the stage
with him while on the campaign trail.

However, the once-close relationship between the two has
soured in recent months following Grillo's expulsion of numerous
dissident MPs from the movement.
So far, 19 lawmakers have been either expelled or resigned
from the M5S in protest at Grillo's aggressive stances.

The movement captured a stunning 25% of the vote in
February 2013 parliamentary elections, with a total of 164 MPs
elected in both houses.